About animals in NT

The Northern Territory (NT) has a huge environmental range that is rich in native animals.

New species of fish, frogs, reptiles, invertebrates and plants continue to be found.

The NT's vertebrate fauna includes 400 bird species, 150 mammal species, 300 reptile species, 50 frog species, 60 freshwater fish species and several hundred species of marine fish.

This includes a few exotic animals that are pests in the NT and have a large impact on native species.

Read about threatened animals in the NT.

Birds

There are few endemic - restricted to the NT - bird species, including the white-throated grass-wren, banded fruit-dove and chestnut-quilled rock-pigeon.

Some of the NT's birds only spend part of their life in the Territory. The coastlines, swamps and water bodies support large numbers of shorebirds, most that breed in the northern hemisphere in their summer. For many of these, the Territory is a stopover as they make their way to southern Australia.

Other NT birds have shorter migrations. The koel, dollarbird, rainbow bee-eater, channel-billed cuckoo and pied imperial-pigeon, or Torres Strait pigeon, make yearly migrations to Indonesia and other parts of south-eastern Australia.

Although some of the rainbow bee-eaters and pied imperial-pigeons are now permanent residents, possibly because of increases in Dry Season food due to ornamental plantings around Darwin.

Mammals

There are a high number of endemic mammal species in the NT, such as the Arnhem rock-rat, black wallaroo, central rock-rat, carpentarian rock-rat, kakadu dunnart, central pebble-mound mouse and kakadu pebble-mound mouse, as well as the bats Taphozous kapalgensis and Hipposideros diadema inornatus.

Many of these are only found in the western Arnhem Land plateau and parts of Kakadu National Park.

The NT mammals include about 35 bat species and 25 marine mammals. Among the latter, there are high numbers of the dugong and snubfin dolphin.

A high number of the Territory's threatened species are mammals.

Many NT mammal species have become extinct either completely, or within the Territory, over the last 100 years.

These include the western quoll, the numbat, desert bandicoot, pig-footed bandicoot, lesser bilby, brush-tailed bettong, burrowing bettong, central hare-wallaby, crescent nailtail wallaby and lesser stick-nest rat.

Threatened mammal species in the NT include the golden bandicoot, marsupial mole, greater bilby, mulgaras and Butler's dunnart.

Many of the Territory's mammals are nocturnal and shy. Most can only be spotted with careful study or camping in the bush at night.

The red kangaroo in Central Australia and the agile wallaby in the north are some exceptions as they are both commonly seen.

Reptiles

Most of the reptiles in the NT are lizards, particularly skinks with over 100 species.

The NT has five common species of marine turtle, including the green, flatback, olive (or pacific) ridley, hawksbill and loggerhead and the leatherback turtle is spotted occasionally.

Territory beaches are important breeding sites for the leatherback, pacific ridley, flatback, hawksbill and green turtles. There are between five and ten freshwater tortoise species.

The saltwater (estuarine) and freshwater crocodiles are a feature of the Top End.

While other notable reptiles include goannas, especially the huge perentie of Central Australia, the frilled neck lizard and the thorny devil.

Snakes are also common and diverse, with about 90 species, including 20 sea-snakes, recorded from the Territory.

NT snakes include the following:

• Oenpelli python, the endemic large snake in western Arnhem Land
• water python which can be seen commonly at night at Fogg Dam
• black-headed python and woma which are beautifully marked snakes that prey largely on other reptiles
• very dangerous snakes such as:
  • the mulga
  • king brown
  • western brown
  • taipan
  • the death adder.

Threatened reptiles in the Territory include several of the marine turtles, three species of goannas that are vulnerable to cane toads and some of the skinks that are restricted to small areas.

Amphibians

Notable NT amphibians include the common green tree frog, the magnificent tree-frog and a range of burrowing frogs, many that appear in Central Australia only after heavy rain.

The chorus of frogs around Wet Season waterholes and flooded forests of the Top End can be remarkable.

There is one threatened frog species in the Territory. The Howard River toadlet lives in sandy areas of the Howard and Elizabeth River catchments, in the outer Darwin area.

Invertebrates

Not much is known about insects in the NT as there is a huge number and variety.

More than 100 ant species may be found within any hectare of the eucalypt forests of northern Australia.

All of the invertebrates listed as threatened species in the Territory are species of land snails or butterflies.

Many land snails are restricted to areas of limestone and/or under fig trees.

In some cases species are only found under one or two individual fig trees or in isolated areas of limestone outcrop.

Landscapes and wildlife

Some parts of the Territory are very important for wildlife as they have an unusual richness of species, or particular groups of endemic or threatened species. Many of these areas are sites of conservation significance in the NT.

The most important area is the stone country of western Arnhem Land, which is home to far more endemic and threatened plants and animals than anywhere else in the Territory.

This is because it is split into deep gorges, caves, escarpments and bouldered slopes.

This provides protection from predators, fire and climatic change.

The area supports many relict species that are either entirely restricted to this area, or have very small numbers and distributions. Many of these relict species are hangovers from periods of far warmer or wetter climates.

Some of the ranges in Central Australia support large numbers of restricted and endemic species. Palm Valley is one such place.

Other parts of the Territory are important because they support abundances of wildlife.

The lowlands and floodplains of northern Australia support large groups of waterfowl, dense populations of fish and crocodiles, and many other species.

At Fogg Dam the population of water pythons has the greatest biomass density for any terrestrial predator system in the world.

Their main prey item, the dusky rat, is in the order of 15,000 individuals per square kilometre.

In other parts of the NT massive groups of wildlife are not a permanent feature.

The long-haired rat plagues in the Mitchell grasslands and chenopod shrublands of the Barkly Tablelands about every 10 to 20 years, which encourages a similar increase in its main predators, the letter-winged kite and barn owl.

The flock bronzewing is another Mitchell grassland species that sometimes occurs in large numbers.

Early explorers described huge flocks of this pigeon darkening the sky for hours as they flew over.